Sometimes, flights are so cheap that they’re obviously not just terrific sale prices, but mistakes. While everybody loves a deal, is booking a secret, mispriced fare tantamount to stealing?

Experienced travelers love to swap insider tips—the location of a secret dinner club in Paris, thoughts on up-and-coming “next Prague” destinations, and, yes, the best deals on airfare all over the world. What happens, though, when an airline’s reservation system makes a mistake, and a flight halfway around the world that should cost, say, $1,800 is suddenly available to book online for just $20?

Well, what sometimes happens is that word spreads quickly about these fares at popular forums like FlyerTalk, and many travelers try to snag the flights at rock-bottom prices before the airline catches the mistake. Consumer advocate Christopher Elliott, who has made a name for himself by helping people to avoid getting ripped off by airlines, hotels, and other travel companies, says that travelers who behave this way aren’t merely unethical, they’re thieves. In a recent post on his blog, Elliott wrote:

Pointing out a fare error online and urging people to book one is like saying someone’s house isn’t locked and urging everyone to steal from it.

The presence of these opportunists gives all of these sites a bad name, and in my opinion, they should be quickly expelled from the group.

Not all travelers agree. Some say Elliott is dead wrong, in fact. In the post, Elliott asked readers to answer the blunt question “Is it ever acceptable to steal from an airline?” Nearly 4 in 10 answered “yes.” Dozens of commenters essentially said that airlines should be forced to honor all flights sold, regardless if a mistake occurred, and regardless of whether travelers booking the flights knew a mistake occurred. One commenter gave this justification:

If a fare can be voided for being an “incorrect price” there’s nothing to prevent an airline from overbooking with higher last minute fares, then claiming it was an “erroneous price” once the passenger gets to the gate to free the seat. As it stands now, the airline is on the hook to get the passenger from one place to another.

In fact, what has happened—and what brought these ultra-cheap mistake fares to light in the first place—is that airlines have canceled such erroneously priced tickets. They’ve typically offered to give customers a full refund, reimburse them for any other nonrefundable travel expenses, and hand over a voucher worth maybe a couple hundred dollars for the traveler’s trouble. For some travelers, the gesture isn’t enough.

In a follow-up post at LinkedIn, Elliott noted that the hatred many passengers feel for the airlines makes it easier for them to try to get one over on the carriers, regardless of whether it’s fair or ethical:

I know the anger many readers feel against airlines. The aviation industry created a sophisticated pricing scheme designed to squeeze the most money out of each passenger, and when it loses control of the system, we shouldn’t let it off the hook, they insist.

In fact, given the horrible things airlines have done in the name of turning a profit, shouldn’t it be our obligation as informed consumers to take advantage of every mistake an airline makes?

Elliott obviously doesn’t think this is the answer. Some of the commenters, however, feel like travelers should take advantage of the airlines in every way possible, to balance things out:

For the other 99.99% of the flying public, those who regularly get taken advantage of by high airfares, rude employees and $9 sandwiches passed off as in-flight meals, who will gladly charge you and I wildly different prices for adjacent seats, they’ve established an adversarial relationship with their customers and are now reaping the benefit of charging for almost everything but the recycled air we breathe on a flight.

Others basically give a “tough noogies” response to the idea that airlines have screwed up and therefore won’t honor the mispriced tickets:

The onus is on the businesses to not make that mistake. Maybe this will serve as a lesson to businesses.